Catalysis

First Principles Approach to Extracting Chemical Information from X-Ray Absorption Near-Edge Spectra of Ga-Containing Materials

Authors

Abstract

The X-ray absorption near edge structure (XANES) can provide uniquely detailed information on the coordination environments of important Ga-containing materials with unknown structures, including catalytically-active materials. In this study, the Ga K-edge XANES was simulated using first principles-based methods for seven molecular Ga complexes, as well b-Ga2O3, in order to explore the chemical origins of the experimentally observed features. The theoretical spectra were computed using FEFF, CASTEP and StoBE, in order to assess the sensitivity of the results to the computational approach. While the XANES features depend on the Ga coordination environment, they are also sensitive to the electronegativity of the ligands and the symmetry at Ga. The white line position responds to changes in both the core state (due to differential screening) and the valence “p” states (arising from differences in ligand coordination).

Content

Thumbnail image of Ga_XANES_Theory_Main.pdf

Supplementary material

Thumbnail image of Ga_XANES_Theory_SI.pdf
Supporting Information: First Principles Approach to Extracting Chemical Information from X-Ray Absorption Near-Edge Spectra of Ga-Containing Materials
Supplementary information: Details of the computational modeling, structures, more detailed comparison, detailed orbital pictures